1,720,965 research outputs found
Isolation of new genes involved in temperature synchronization of the circadian clock of Drosophila melanogaster
No full textPhDCircadian clocks regulate behaviour and physiology of many organisms and keep
them in synchrony with the environment. Drosophila's circadian clock is mainly
synchronized by natural light-dark cycles and temperature
fluctuations, both at
molecular and behavioural levels. The mechanisms underlying temperature entrainment
are poorly understood, but previous studies have shown that this process
can be genetically dissected.
In this work, I isolated several mutants which interfere with the temperature
synchronization of Drosophila's circadian clock. Three variants were isolated
in a chemical EMS-mutagenesis screen monitoring putative second- and thirdchromosomal
mutations. The mutants behave normal in light-dark cycles suggesting
that they specifically interfere with temperature entrainment. In a different,
RNAi-based screen, a Forkhead-domain transcription factor encoding gene was
isolated, which shows defective circadian activity of per expression and PER accumulation
in temperature-entrainment condition, when down-regulated. Finally,
a candidate approach led me to identify three genes encoding proteins belonging
to the TRP family of ion channels. Mutations in the pyrexia, trpM and trpA1
genes show abnormal temperature synchronization of locomotor behaviour, similar
to our EMS-candidates.
The isolation and analysis of those mutations are described, as well as a behavioural
analysis of the already-known "temperature-mutant" nocte. In particular,
I discuss the involvement of chordotonal organs as structures required for
temperature entrainment of the clock and the role of nocte for signalling the temperature
information from the periphery to the brain.
The rest-activity pattern is a well-studied circadian output behaviour; the pupal
emergence, named eclosion, is another behaviour strictly regulated by the circadian clock. Here we show that genes important for entrainment of adult locomotor
behaviour to temperature do not play the same role in regulating the synchronization
of eclosion. To gain insight into the synchronization mechanisms of eclosion,
I studied how different entrainment conditions affect the phase and free-running
period of eclosion
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
